Faulty electrical wiring is to blame for yesterday’s three-alarm blaze that scorched part of the South Street Seaport’s boardwalk, fire officials said.

The wires — which are located under Pier 17 and provide power to its lights, vending machines and kiosk outlets — sparked a blaze that send huge plumes of smoke billowing through the Lower Manhattan tourist spot at about 4 p.m., officials said.

Approximately 150 firefighters brought the flames under control by 6 p.m. No one was hurt.